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ULTRASONIC GENE ZATION OF AN AQUEOUS NICOTINE AEROSOL FOR SUBJECTIVE TESTING Peter J. Lipowicz 2 April 1991

HYPOTHESIS: SUBJECTIVE RESPONSE TO NICOTINE AEROSOL CAN BE ALTERED BY CHANGING AEROSOL PH • Impact • Physiological response • Protonated nicotine vs. basic nicotine

RESEARCH PLAN • Generate nicotine aerosol at controlled~ pH • Measure subjective response with panelists • Determine validity of hypothesis • Determine applicability of hypothesis

CHARACTERISTICS OF THE IDEAL AEROSOL GENERATOR • Subjectively neutral matrix • Controllable and sufficient nicotine concentration • Controllable aerosol pH • Steady and reproducible output • Amenable to panelist testing

THE ULTRASONIC AEROSOL GENERATOR • Generates aqueous solution • Aerosol composition is same as solution composition • Nicotine concentration of solution can be varied • pH of solution can be adjusted with addition of acid • Can generate high concentrations, • Compact commercial units available

G.n4rator R.stfrotr (E): G.ys.r(0)

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ISSUES IN THE DEVELOPMENT OF THE TEST PROTOCOL • Nicotine level -- 20'to 30 ug per puff • Acid to adjust pH -- phosphoric acid • Measurement of aerosol pH -- pH paper • Isotonicity of solution -- not controlled • Sterility of solution -- filter sterilized • Sterility of generator -- autoclaved'~ • Nicotine concentration in aerosol -- spectrophotometry • Venting excess aerosol -- installed hood in Frank Gullotta's laboratory • Sampling prodecure • Reproducibility of aerosol production • Physical nature of aerosol

REQUIREMENTS OF SAMPLING PROCEDURE • Simplicity • Delivers controlled volume of aerosol • Similarity to cigarette -- inhalation by puffs -- puff volume -- pressure drop -- size of mouth end

STABILITY AND REPRODUCIBILITY OF AEROSOL OUTPUT • Required so that nicotine level can be controlled • Medium rate ( 1 g/min ) is not reproducible -- varies for different aqueous solutions • High rate(4.5 g/min ) isbetter-- less affected by solution composition